German Patent No. DE 10 2014 018 643 B3 describes the generation of a voltage-reference value from a plurality of measured values of control units in a central master device. The control units are equipped with voltage-measuring devices and make the measured voltage values available to the central master device; the central master device then supplies the reference value to each control unit, so that they are able to ascertain a correction value for calibrating the voltage-measuring device.
German Patent No. DE 10 2004 023 084 B3 describes a method for monitoring the voltage in a vehicle-device system; in this instance, a control unit monitors for the presence of an undervoltage by comparing the applied actual voltage to a predefined lower voltage threshold.